Water-Dispersible Polymer Powder for Subterranean Cementing
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Solution Overview
Problem
Current cement formulations for wellbore cementing face challenges such as rapid setting, fluid loss, and gas migration due to hydrostatic pressure and temperature variations, which affect the strength and integrity of the cement bond, and existing additives like aqueous latex dispersions are prone to coagulation, frost damage, and biological decomposition.
Innovation Solution
A water-dispersible polymer powder composition comprising 50-98.5% styrene-butadiene polymer, 1-20% water-soluble polymer, and 0.5-10% non-ionic emulsifier, where the styrene-butadiene polymer particles are partly covered or embedded in the water-soluble polymer, and the composition is produced by spray-drying an aqueous dispersion with added non-ionic emulsifier, providing improved anti-fluid-loss properties and rectangular setting behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aqueous latex dispersions are used as anti-fluid-loss additives, then fluid loss control is improved, but the additives are prone to coagulation, frost damage, and biological decomposition
Solution Approach 1:
The patent applies phase transition by converting the aqueous latex dispersion from liquid phase to solid phase through spray-drying. The aqueous dispersion is atomized into droplets that rapidly evaporate water, forming free-flowing polymer powder. This phase change eliminates the water continuous phase that causes coagulation and biological decomposition, while the resulting powder maintains stability under various conditions including frost.
Solution Approach 2:
The patent changes the physical state parameter of the additive from liquid dispersion to solid powder. This parameter change fundamentally alters the stability characteristics, eliminating susceptibility to coagulation and biological decomposition while maintaining fluid loss control functionality. The powder form also improves storage and handling properties.
2Duration of action of moving object
If cement slurry is kept pumpable for extended periods, then cement placement flexibility is improved, but the cement sets too quickly and loses pumpability
Solution Approach 1:
The polymer powder is incorporated into the cement slurry before placement, performing preliminary action by establishing a protective network that prevents rapid water loss from the slurry. This preliminary protection maintains slurry fluidity and pumpability for extended periods, allowing flexible placement operations without compromising eventual cement set strength.
Solution Approach 2:
The polymer acts as an intermediary substance between the cement particles and water. It modifies the water-cement interaction by forming a protective layer that controls water loss rate, thereby extending the time window for pumpability while ensuring reliable setting. The polymer mediates the balance between maintaining fluidity and enabling eventual strength development.
3Stress or pressure
If hydrostatic pressure is applied to cement slurry in long wellbores, then cement placement is facilitated, but water filtration into formation occurs causing fluid loss
Solution Approach 1:
The polymer powder provides preliminary anti-action by forming a protective network in the cement slurry before hydrostatic pressure is applied during placement. This pre-established network resists the filtering action of hydrostatic pressure, preventing water from penetrating into the formation. The polymer counteracts the harmful filtering effect before it can occur, maintaining slurry integrity throughout the cementing operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition significantly reduces fluid loss and maintains a low gel strength for extended periods, ensuring the cement slurry remains pumpable and rapidly increases in strength upon placement, enhancing the cement's ability to withstand hydrostatic pressure and temperature variations.
Implementation Method 1
0.5 to 10 wt.-% of at least one non-ionic emulsifier (C)... wherein the styrene-butadiene polymer particles are at least partly covered by and/or embedded in a composition (X) comprising at least the water-soluble polymer (B)
Implementation Method 2
a process of making such compositions, by spray-drying an aqueous dispersion comprising said particles of a styrene-butadiene polymer and a water-soluble polymer
Data Source
AI summary
Water-dispersible polymer powder composition for use as additive in cementing in subterranean formations comprising at least particles of a styrene-butadiene polymer, a water-soluble polymer, and a non-ionic emulsifier, wherein the styrene-butadiene polymer particles are at least partly covered by and/or embedded in a composition comprising at least the water-soluble polymer, process of making such compositions, by spray-drying an aqueous dispersion comprising said particles of a styrene-butadiene polymer and a water-soluble polymer, wherein at least one non-ionic emulsifier is added before or after spray-drying, and the use of such water-dispersible polymer powder compositions for cementing in subterranean formations penetrated by at least a well bore.